ASA 126th Meeting Denver 1993 October 4-8

3aAO3. Estimating vertical and horizontal wave-number temperature spectra of a buoyant thermal plume.

John Oeschger

Univ. of Rhode Island, Dept. of Phys., Kingston, RI 02881

Louis Goodman

Naval Undersea Warfare Ctr., Newport, RI 02841

Acoustic scattering from a buoyant thermal plume described by the far-field Born approximation results in a simple relationship between the scattered pressure field and the scattering field; namely, the two are Fourier transform pairs. For media variability, such as the buoyant plume where the spatial variability is larger than the Fresnel radius, wave-front curvature must be included to describe experimental results adequately. Under conditions where Taylor's hypothesis is satisfied (the time variability is entirely due to the advection at a constant velocity of spatial variability), the effects of wave-front curvature on the scattering process can be removed. Data are collected for simultaneous multiple bistatic scattering experiments in common and antiparallel scattering directions for the unstable and turbulent plume. Results include an estimation of the vertical and horizontal wave-number temperature spectra of the buoyant plume.